Duplex fluid strainer



April 25, 1950 J. c. WOHLFARTH DUPLEX FLUID STRAINER Filed Dec. -28, 1948 2 Sheets-Sheet l.

MK w i atenteci Apr. 25 195 2,505,375 "D PLEXFLUms'rRAIN R John 0. Wnhltarth,.Harrisburg, Pa assi gnor Bethlehem Steel Company, a orr t on aof ennsy vania Appli'eacien' December 28, 1948;8e1ia1No:- 67;709

4.4 .Glaims.

This invention-relates to strainers or use in removing suspended matter f-rem fluids, and is particularly directed to an improvement in fuel on strain-er units of the duplex-type :eomprising duplicate strainer -elements such as are known to be used in an -burning-"systeins where it issa matter of especial importance that there :shall be no inadvertent interruption of the normal flow of the strained fuel oil to its paint :ef ruse er-consumption.

KnoWn -fuel e'il strainers ef the duplex type usualiy eomprise within their design theinherent ability -t-sht1t ofi :one of the 7 two strainer .elemeets when under normal operating conditions for talic purlp0se ef inspection of and repair Lto g the element 'shu-t -ofi without interrupting the normal: flowmf iuellc il through the other ref its strainer elements to its point -of -use.or consumption. In-some strainers this=desi1tab1e feature is acoemplished automatically; by. having :a single 'retatable gate type of valve that serves both vidual :inlet -.andf :discharge -valves :ataopposite ends thereof whereby the. inlet .and-idischargezends .nf eaehstrainerelement may .-be individually opened up or shut 0ft," as to ffiow therethrough, 3.86166,- tively by thereperatoriof the'zstrainer unit. An

example-M this type 50f strainer unit is disclosed in the Patent 1,621,186 =to..Lalor, of iMayJI3 1192IZ. Thelialorfstrainer .unit is well-,adapted ior high liquid J -pressure' fuel oil burners, ibuti this design has =Ithe disadva'ntage thatsit adepends' puponrthe operator -thereof fer proper operation thereof, and it can-.berinadvertently shut ioff entirely during operation. My. invention lies: in: an .im-

"pmvement for :theLalor type of duplex 'fuel eil strainer units to; prevent inadvertent maloperr gtionithereof- It istheJ-primary' object :of my invention :110 construct a duplex i-u'el oilstraineruhit comprising' internally thereof 2a 1 1 duplication toffstrainer elements; eaehaabfzesaid elements comprising iinlet ioutlet wvalve fluid .aopemngs adapted more matesrthezcompleteensemble of aduplexeflfinfil manual iclosure:thereofkbysmeans ofiaxiallymev ablezserew stemmed zdisc valves having .external operating. handlesiattached to the outer end ref said valve s stems, a the .said .external .ends of .Jsa-i'd valve stems recuperating as re. :group withiinterlocking menitor means zwhereby wither some 1101: said strainer elements may iibe shut gofi :singly for:inspectionionrepairphuna condition 10f: simultaneous shut aofi of both strainer 1 elements. dur, ingiznormaleperationaofrthestrainer unit is; automatically prevented, and inadvertentmalope ation thereofais precluded.

It .is a rurtlaer 5.0133663 not my invention :that the :shut off rendition of :a selected strainer element .imayIbe aaccemplished .;by @the "closing :ef either one 101' -'..bo.th 11f thexinleteand .ontlet .valve openings of fthe z-seleetedxstrainer element, and that wlment'so. shut .efiqneither one :ofzthe valves of .the other .strainer :element Emay abe :closed Without first opening said; first? mentionedwalve .01 valves, :whereby '..the uninterrupted :flow :ao'f strainer fuel oil through said -1strainer wunitzis assured.

.It is. a ftfurther cobject 101? any: invention :that at any time during :normal operation 16f rthe strainer mnit tall ifour valves tnereof xmay vshe fully ;opened,; ;and nthus. have both-"strainer :eleenemas .in voperation J .if :rleemed desirable.

It is;- another .ebject of. myiinventienethatreelecti-ve' closinga-oflany isinelez-walve may be laccam plishedzzonlywheniialkffuurvvalveszzare: fully open, and .that 2' successive closing of a the valves visits!) monitored. as -to permit only e01: i nqrmalrninter- .rupted. operatiomof itheistrainer Further subjects rand sad-vantages will be .-:a-p.- parent iirom ithe following description wherein details: of design; andsoperation .will :be givenein full with; .reierenee i-to the accompanyin drawings illustrating :the ,npreferred :jembodiment .pf my invention, and wherein wsimilar sreferenee numerals designate asimilar sparts;througnou .jgly e severalviews.

Fig/= 1 is=a;. plan'-view:of .aistrainer .Un tuincorporating thespreierredz form 2913mm invention,

:Ftig. :2: is ax-vertieallcsectional viewzxtalgen along the line 2..2 of Big. .11 as; seenlziqn heud l-fiqijfll of the arrowswZ-Z,

Fig:3;is asiull-rearyiew as seen-iin'the dir etie ofirarrows 4- 4-1013 *F -alw nd Fig.3 4 .is a rszenticalzseetionaleview rtalienealgng the line 4--1-430ffFig.i-]; as-seen 5111 151516, idirectiqnz of cthe' arrowszd-ei Referring now toztheizdrawlingseand :moreaparinsular-1y to;v Figs-ziiandfiwtne; .numeralifl desigunit embodying the preferred form of my invention.

The duplex strainer unit If] comprises a main housing I l divided into two parallel substantially cylindrical body portions 12 and 13 which serve to house the substantially identical strainer elements l4 and H5. The main housing II has downwardly extending rear foot supports It and I1, and front supports i8 and 19, each adapted with apertures for foundation attachments (not shown). Extending integrally upward from the body portions 52 and 13 at the rear thereof are the inlet valve housings 2i and 22, respectively; and, at the front thereof are the outlet Valve housings 23 and 24, respectively. Transversely and jointly uniting the body portions i2 and I3 and their respective valve housings 2i to '24, inclusive, are the integral web portions 25 and 2S, and the cylindrical portions 2? and 28 (see Figs. 2 and 3). Extending integrally outwardly from the inlet valve housings 2| and 22 are the dual flanged inlets 2a and 3t, and extending integrally outwardly from the outlet valve housings 23 and 24 are the dual flanged outlets 3| and 32. The dual flanged inlets and outlets are adapted to be connected to the oil conduit between the oil supply tank and the burners in any desirable or conventional manner. As indicated in the drawings the dual flanged inlets and outlets are adapted with apertures 33 for conventional bolted flanges (see Fig. 2).

Referring now particularly to Fig. 4 we have here a vertical cross sectional view through the strainer unit It along the line 44 of Fig. 1. This view is taken through the inlet valve ends of the strainer elements l4 and I asseen from the rear thereof and except for respective designating numerals it is typical of that prevailing at the outlet ends of the strainer elements l4 and I5, and therefore a description of Fig. 4 showing the inlet valve end structure will sufiice for an understanding of the outlet valve end structure, and need not be repeated for the latter except for certain features inclusively stated in the description for the inlet valve end structure. The inlet valves 34 and 35 together with the outlet valves 36 and 3'! (Fig. l) are preferably uniform in design and may be of any suitable internal structure that comprises an external axially movable screw type valve stem 38 having an abutment 39 thereon. -As shown in the drawings the stem 33 s -mounted in a packed bonnet 49 suitably attached to the housing II, and is provided with a suitable disc valve 4| and an external manually operable means such as handwheel 42. As will be noted in Fig. 4 an inlet valve chamber 43 extends succ'essively through the flanged inlet 29, the inlet valve housing 21, the cylindrical portion 2'1, the inlet valve housing 22, and the flanged inlet 30. A- similar outlet valve chamber 44 (Fig. 2) extends successively through the flanged outlet 3!, the outlet valve housing 23, the cylindrical portion 28, the outlet valve housing 24, and. the flanged outlet 32. The inlet and outlet valve chambers 43 and 44 are each adapted with openings 45 for mounting the bonnets 46 of the valves 34, 35, 36, and 31; and are each further adapted. with suitable valve seats 46 for disc valves 4|, and communicating valve openings 41 which communicate the inlet and outlet valve chambers 43 and 44 with the strainer chambers (48 and 49) below to be further described hereinafter. The inlet Valve chamber 43 receives the flow of fuel oil from the fuel supply tank conduit (not shown) and passes it on to and through the outlet valve 4 chamber 44 to the conduit for the burners (not shown), as will now be described.

Referring now particularly to Fig. 2 we have here a vertical cross sectional view taken through the strainer unit I0 along the line 2-2 of Fig. 1. This view is taken longitudinally through the strainer element It and includes its control meansthe inlet valve 35 and the outlet valve 31. A similar View if taken through the strainer element l4 would be substantially identical to that of the strainer element i5 except for designating numerals, and therefore a description of the one will suffice for a full understanding of the other, and need not be repeated except for certain features inclusively stated in the description now to be given for the strainer element i5. The main housing ll comprises the two strainer chambers 48 and 49 extending lengthwise in parallel relationship within the body portions l2 and I3 respectively thereof, and communicating with the inlet and outlet valve chambers 43 and 44 directly above at each end thereof through the valve openings 4? of the valve housings 2|, 22, 23, and 24 in their respective locations as has been described hereinabove. The strainer chambers 48 and 49 are each closed at the front end thereof by wall portions 59 of the main housing ll, and are open at the rear end thereof. Each rear end of the chambers 48 and 49 is adapted with readily removable closure means 5|. As shown in the drawings the closure means 5| comprise a closure head 52 with sealing gasket 53, a clamp screw 54 having a rotatable tongue-andgroove engagement at its inner end with the closure head 52, and held in engagement therewith by retainer strip 55 and fastening means 56 (Fig. 3), and a latch bar 51 adapted centrally for threaded engagement with the clamp screw 54, and having oppositely extending side slotted ends 5S-the sides 59 of the slots being concentric with the axis of the clamp screw 54 for the purpose of rotational engagement and disengagement with the shouldered latch studs 68 mounted in the rear face of the housing H adjacent each strainer chamber opening. Each of the latch studs 69 is provided with shouldered extensions 6| having abutments 62 adapted to provide clamping resistance when engaged with the slotted ends 58 of the latch bar 51. When the latch bar 5? is in engagement with the extension abutments t2 the clamp screw 54 may be adjusted inwardly or outwardly as desired to seal or to release the closure head 62 with relation to its respective strainer chamber.

The strainer chambers 48 and 49 each comprise an internal annular abutment flange 63 slightly to the front of the inlet valve opening 41. Each strainer chamber 48 and 49 is provided with a foraminated strainer cage 64 having an open rimmed rear end 65 adapted to seat on the abutment 63, and a closed front end 66. The rimmed rear end 65 is adapted with a bail 61 whereby when the closure head 52 is clamped in place its inner surface engages the bail 6? and forces the rimmed rear end 65 of the strainer cage 64 to seat against the annular abutment 63.

In operation the strainer unit [0 as hereinabove set forth will receive oil from the oil supply tank through either one or both of its in-.- lets 29 and 30 as desired (the unused inlet, if any, being shut off in any conventional manner) and flowing through the unit I 9 the oil will be strained, and Will be delivered to the burner conduit through either one or both of its outlets 3! and 32 as desired (the unused outlet, .if

eases s ansag eingsnet seas" the case or 'theifilets" zli s" to beuii'drs'tood that it isa'donditi'on of f operatronof invention when in use strainer unit it shall be adapted to have inlet valves in communication with s 'soureego'f on supply, and to have both of its outiet" valves in communication with a conduit to the burners in "operation thereunder. I have li'iifisliown the preferred form of my apparatus, safaris obvious" that the inlet valve chamber 13 and the outlet valve c'zhamber' 44 could each divided into" individual chambers for each valve; and that each such chamber could be properly serviced within the herein disclosure witfidnt departing from the spirit or scope of this invention, or sacrificing any of its ad- Vai'it s. I

typical operating routine for the strainer It may be traced'on the drawings as fol lows? H iieferringto Fig. 1 assume that oil is being de liYfdtb and discha ged from the strainer unit Iii in amorean'eewith the preceding paragraph; aiidthat the strainer element M'is in normal oprating annu ties, and that the strainer element It shit on and may be opened for the purpose df'cleaning the strainer'cage 64. Referring "a; Fig. 4 the implied condition of internal offifati'on is shown wherein the inlet valve 34 of the strainer" element lais in full open positionwith its disc valve 41 raisedabove its valve seatl fi'soas to allow oil flowing into the inlet manner 43 from the connected tank conduit (not shown) to flow through the communicating valve opening l? into the strainer chamber below, while at the same time the inlet valve 35 of the strainer element I is in its closed position with its disc valve seated upon its valve seat thus preventing oil within the inlet chamber 43 from flowing into the strainer chamber 49 below. By referring now to Fig. 2 we note that this view shows theimplied condition of shut off existing in the strainer element t5 wherein both the m let, valve and the outlet valve 3? are closed whereby oil cannot flow from either the inlet chaniberfl or the outlet chamber into the strainer chamber 49' below, and the chamber 49 may therefore be safely opened for examination, or repair and cleaning of the strainer cageB l. With a little imaginaticn Fig. 2 may also be used to illustrate the flow of oil through the strainer element M as isioeeurnng at the same time as is the shut ofi condition of strainer element I 5. By temporarily ignoring the indicating numerals and assuming that Fig. 2 discloses the strainer element M with its inlet valve andits outlet valve open; then the oil flows from the inlet valve chamber above through its communicating inlet valve ripening to the rear of the strainer chamber below, and flowing forwardly through the strainer cage leaves the strainer chamber at the front end thereof through the communicating outlet valve Opening into the outlet valve chamber above, and. thence to the burner conduit (not shown), thus completing its cycle through the strainer unit It.

We now come to that feature of the strainer unit [0 which constitutes my invention per se when used in cooperation with the strainer unit l0. Mounted upon the longitudinal axis of the unit l0 and suitably attached to the upper surfaces of the valve bonnets thereof by certain fastening devices 68 thereof are the rocker shaft support brackets 69 and "It. The support brackets and To provide bearing means for-the rocker shaft rotatable therein. Attached to therock-er shaft If by any suitablemeans such as welding 12 are" the? dual twin-armed monitor levers l3 and i4; Lever 13 serving" theinlet valves 34' and 35, and lever 14 serving the outlet valves 36% and 3l; The monitorlevers iii-and It are identi cal in structure, are in alignment upon the rocker shaft if, and have the ends 15 of their outwardly eiitendi-ng arms each adapted for facial engagement with the valve stem abutment 39 of its respective valve (Fig. 4 The angular relation-- ship of the twin arr'nsin each of the levers l3 and Mare identical and are such that when all the valves of both strainer elements l5 and I5 are at full'open position any one valve stem 38 may beadjusted downward to its full closed position and in so doing'the' abutment 39 of this valve stem will engage the outer end 1'5 of its respective monitor lever pushing it downward, and will thereby'rotate the rocker shaft H and both'levers I3 and M thereon about its axis, whereby the lever ends '15 on both of the levers I3 and 14 on the opposite side of the rocker shaft H to that of the depressed ends 15 will rise and engage the abutments 39 of both the valve stems on that side in their full open position, thus preventing any downward movement of either of these valves in a closing direction until the first closed valve (01: valves) is or are again opened. It will be understood that the shut off condition of a strainer element with respect to the flow of oil therethrough may be brought about by the closing of either one or both of the valves controlling that specific strainer element. For the examination Of the strainer cage both valves of itsstrainer element must be closed to prevent'the escape of oil therefrom when opened. When both valves of a-strainer element have been closed then both of these valves must be opened before either one or both valves of the other strainer element may be closed. In order to avoid unnecessary enactitude in timing, an overtravel clearance is allowed for in theopen position of each valve as-is indicated at Hi between the top of each disc valve ll and the inner face of its bonnet 40 These clearances in no way affect adversely the automatic safety functioning of the strainer unit H).

t will now be readily apparent to those skilled in the art to which this invention appertains that I have made an improvement in the specific-type of duplex oil strainer unit herein described (wherein individual inlet and outlet valves are provided for each of the strainer elements) whereby either one of two strainer elements may be out ofi singly for inspection or repair, but (a condition of simultaneous shut off of both strainer elements during normal-operation of the strainer unit is automatically prevented; and inadvertent malopera'tion or the strainer unit is precluded. In the Lalor device the operator could either intentionally or inadvertently shut ofi a second strainer element when a first one was already shut ofi. In my improvement a second strainer element can not be shut off when a first strainer element is shut off, but the second strainer element may be shut 01f successively by first opening up the first shut off strainer element-this constitutes the safety feature that prevents and precludes maloperation.

I claim:

1. A duplex fluid strainer unit comprising internally thereof a duplication of strainer elements, each of said elements comprising inlet and outlet asoasvs flow control means in spaced relation along the axis thereof, each of said control means being adapted for manual closure thereof by means of external operating handles, a rocker shaft operably mounted upon said unit axially midway be tween the respective axes of the said strainer elements and between their external operating handles, rocker arms fixed upon said shaft in line with each of said operating handles, the outer end of each said rocker arm being adapted to engage the under side of its respective adjacent operating handle when the control means of one of said strainer elements are both closed and the control means of the other of said strainer elements are both open, whereby in subsequent normal operation of the strainer unit either one or both of the control means of either strainer element may be operably closable only when both of the control means of the other strainer element are open.

2. A duplex fluid strainer unit comprising internally thereof a duplication of strainer elements, each of said elements comprising inlet and outlet valve fluid openings at opposite ends thereof, conduit means for supplying fluid to each of said inlet openings, conduit means for discharging fluid from each of said outlet openings, axially movable screw-stemmed valve for each of said openings, the said valve means each comprising external manually operable means having an inwardly facing abutment thereon, a rocker shaft operably mounted on said unit substantially midway between the strainer elements and between the said external operable means, two double-armed rocking levers fixed upon said shaft in spaced relation in line with said inlet valves and said outlet valves respectively, the outer end of each said rocking lever being adapted to facially engage their respective adjacent valve stem abutment when the valves of one of said strainer elements are both closed and the valves of the other of said strainer elements are both open, whereby in subsequent normal operation of the strainer unit either one or both of the valves of either of said strainer elements may be operably closable only when both of the valves of the other of said strainer elements are open.

3. A duplex fiuid strainer unit comprising internally thereof a duplication of strainer elements having their axes spatially parallel in a common plane, each of said elements comprising inlet and outlet valve fluid openings at opposite ends thereof, the said inlet openings and the said outlet openings having their axes each lying in common planes respectively spatially parallel to each other, conduit means for supplying fluid to each of said inlet valve openings, conduit means for discharging fluid from each of said outlet valve openings, axially movable screw-stemmed valve means for each of said valve openings, the said valve means each comprising external manually operable means having an inwardly facing abutment, a rocker shaft operably mounted on said unit substantially midway between said strainer elements, two double-armed rocking levers fixed transversely upon said shaft in spaced relation proximate the planes of the said inlet and outlet valve openings respectively, the outer ends of the said levers being each adapted to facially engage their respective adjacent valve stem abutment when the valves of one strainer element are both closed and the valves of the other strainer element are both open, whereby in subsequent normal operation of the strainer unit either one or both of the valves of either strainer element may be operably closable only when both of the valves of the other strainer element are open.

4. A duplex fluid strainer unit comprising internally thereof a duplication of strainer elements having their axes spatially parallel in a, common plane, each of said elements comprising inlet and outlet valve fluid openings having their axes spatially parallel in a common plane, said latter planes being spatially parallel one to the other and normal to the first mentioned plane, and having the axes of the inlet openings and of the outlet openings respectively in spatially parallel common planes that are transverse to the first mentioned axes and thereby normal to all three first mentioned planes, conduit means for supplying fluid to each of said inlet valve openings, conduit means for discharging fluid from each of said outlet valve openings, axially movable screwstemmed valve means for each of said valve openings, the said valve means each comprising external manually operable means having an inwardly facing abutment, a rocking shaft operably mounted upon said unit parallel to the axes of said strainer elements and substantially midway between the second and third mentioned planes, two double-armed rocking levers fixed transversely upon said shaft in spaced relation proximate the planes of the said inlet and of the said outlet valve openings respectively, the outer ends of the said levers being each adapted to facially engage their respective adjacent valve stem abutment when the valves or" one strainer element are both closed and the valves of the other strainer element are both open, whereby in subsequent normal operation of the strainer unit either one or both of the valves of either strainer element may be operably closable only when both valves of the other strainer element are open.

JOHN C. WOHLFARTH. I

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 218,351 Weed Aug. 5, 1879 1,627,186 Lalor May 3, 1927 

